As an example of conventional leakage current reducing apparatus, the following high-frequency leakage current reducing apparatus is known. That is, in order to reduce a high-frequency leakage current occurring in three-phase power supply lines connected between an inverter apparatus and a three-phase motor, the high-frequency leakage current reducing apparatus comprises: a current detection coil for detecting the high-frequency leakage current; high-frequency amplification means for amplifying the detected high-frequency leakage current; and a matching coil for electromagnetically injecting the amplified high-frequency leakage current, in the opposite phase, to the three-phase power supply lines (for example, see Patent Document 1).